Unity crashes at startup after update to 5.1 from 5.02

I can’t start Unity anymore after updating to latest editor version.

In the editor log I get the following:

LICENSE SYSTEM [2015620 20:29:48] No start/stop license dates set

LICENSE SYSTEM [2015620 20:29:48] Next license update check is after 2015-06-21T13:41:27

Can anyone help? I’m pretty sure this is a bug, but is there any work around?

Remove Library folders in all your projects and reinstall the editor.